1. Field of the Invention
The present invention relates generally to coaxial cable connectors.
2. Technical Background
Coaxial cable connectors such as F-connectors are used to attach a coaxial cable to another object such as an appliance or device or junction having a terminal adapted to engage the connector. Coaxial cable F-connectors are often used to terminate a drop cable in a cable television system. The coaxial cable typically includes a center conductor surrounded by a dielectric, in turn surrounded by a conductive grounding foil and/or braided shield, hereinafter collectively referred to as the outer conductor; the outer conductor is in turn surrounded by a protective outer jacket. The F-connector is secured over a prepared end of a jacketed coaxial cable, allowing the end of the coaxial cable to be connected with a terminal block, such as by a threaded connection with a threaded terminal of a terminal block, or with an adapter such as a female adapter that accepts the center conductor of the cable and has threads for threaded connection with the F-connector.
Crimp style F-connectors are known wherein a crimp sleeve is included as part of the connector body. A special radial crimping tool, having jaws that form a hexagon, is used to radially crimp the crimp sleeve around the outer jacket of the coaxial cable to secure such a crimp style F-connector over the prepared end of the coaxial cable. An example of such crimp connectors is disclosed within U.S. Pat. No. 4,400,050 to Hayward.
It is known in the art that the passage of moisture between the coaxial cable jacket and the surrounding F-connector can lead to corrosion, increased contact resistance, reduced signal strength, and excessive RF leakage from the connector. Various efforts have been made to form a seal between the F-connector and the jacket of the coaxial cable to preclude such moisture ingress. F-connectors are known in the cable television industry which utilize special sealing compounds in an effort to form leakproof seals. For example, U.S. Pat. No. 4,755,152 to Elliot, et al., discloses a crimp connector incorporating a glob of a gel or other movable sealing material within a cavity of the connector to form a seal between the jacket of the coaxial cable and the interior of the F-connector.
Still another form of F-connector is known wherein an annular compression sleeve is used to secure the F-connector over the prepared end of the cable. Rather than crimping a crimp sleeve radially toward the jacket of the coaxial cable, these F-connectors employ an annular compression sleeve that is initially attached to the F-connector, but which is detached therefrom prior to installation of the F-connector. The compression sleeve includes an inner bore for allowing such compression sleeve to be passed over the end of the coaxial cable prior to installation of the F-connector. The F-connector itself is then inserted over the prepared end of the coaxial cable. Next, the compression sleeve is compressed axially along the longitudinal axis of the connector into the body of the connector, simultaneously compressing the jacket of the coaxial cable between the compression sleeve and the tubular post of the connector. An example of such a compression sleeve F-connector is shown in U.S. Pat. No. 4,834,675 to Samchisen which discloses a compression sleeve type F-connector known in the industry as “Snap-n-Seal”. A number of commercial tool manufacturers provide compression tools for axially compressing the compression sleeve into such connectors.
Another known connector is the radial compression-type F-connector such as disclosed in U.S. Pat. No. 5,470,257 to Szegda. A tubular locking member protrudes axially into the open rear end of the outer collar or sleeve. The tubular locking member is displaceable axially within the outer collar between an open position accommodating insertion of the tubular post into the prepared end of the coaxial cable, and a clamped position fixing the end of the cable within the F-connector. An O-ring is mounted on the rear end of the tubular locking member to seal the connection between the tubular locking member and the outer collar as the tubular locking member is axially compressed. Such connectors have been sold in the past under the designation “CMP”. The O-ring provided on the tubular locking member is exposed and unprotected prior to axial compression of the F-connector.
Known coaxial cable connectors employ collars or sleeves which can be compressed inwardly against the outer surface of a coaxial cable to secure a coaxial cable connector thereto. For example, a connector assembly for a signal transmission system is disclosed in U.S. Pat. No. 4,575,274 to Hayward wherein a body portion threadedly engages a nut portion. The nut portion includes an internal bore in which a ferrule is disposed, the ferrule having an internal bore through which the outer conductor of a coaxial cable is passed. As the nut portion is threaded over the body portion, the ferrule is wedged inwardly to constrict the inner diameter of the ferrule, thereby tightening the ferrule about the outer surface of the cable. However, such connectors can not be installed quickly, as by a simple crimp or compression tool, but instead mating threads of such connector must be tightened, as by using a pair of wrenches.